1. Technical Field
The present invention relates to a light deflector, using a micro-electro-mechanical system (MEMS) technology, a method of manufacturing the light deflector, and an image display device.
2. Related Art
In the light deflector intended to be applied to, for example, a display or a printer for performing image drawing using a laser beam, further speeding-up of light scanning is required in order for improving the resolution of the image. However, since there is a limitation on the improvement in the performance of polygon mirrors or galvanometer mirrors used presently, a mirror device manufactured by working upon a silicon substrate using a micro-electro-mechanical system (MEMS) is thought to be a promising light deflector replacing these elements. Since such an MEMS mirror can be driven at a resonant frequency higher than those of the polygon mirror and the galvanometer mirror, it becomes possible to form images with higher resolution.
In the MEMS mirror the laser beam is applied to the mirror section, and the object is irradiated with the reflected light, thereby performing the image drawing. If the light is reflected by other sections than the mirror section, there is concern that the reflected light exerts an influence on the image as stray light. Therefore, there has been made a device for preventing the stray light as much as possible by providing an antireflection film to the portions other than the mirror section.
In JP-A-2006-39156 (Document 1), for example, there is disclosed a planar actuator having a planar movable plate, a pair of torsion bars for rotatably pivoting the movable plate, and a mirror section provided to the movable plate, and provided with an antireflection film on the portion other than the mirror section.
Further, in JP-A-2005-107069 (Document 2), it is described to reduce the reflexibility of beam sections and fixed sections in an optical scanner, to which unwanted light is input, reflecting the light so as to be lower than that of the reflecting surface.
When forming the antireflection film using a typical film formation method such as a sputtering process or a plating process, if the side surfaces of the movable plate and the torsion bars are formed substantially perpendicular to the upper surface, it is difficult to form the even antireflection films on the side surfaces. However, since the reflection on the side surface of the movable plate also occurs by turning the movable plate, it is desirable to provide the antireflection film also to the side surface. In the actuator described in the Document 1, since the side surface of the movable plate is arranged to be substantially perpendicular to the surface, it is difficult to provide the side surface with an even antireflection film. Further, in the optical scanner described in the Document 2, it is desirable to form the even antireflection films also on the side surfaces of the beam sections and the fixed section.
As described above, in the actuator described in the Document 1, since the function of preventing the light reflection on the side surfaces of the movable plate, the torsion bars, and so on becomes insufficient, there arises a problem that the light is reflected by the side surfaces of the movable plate, the torsion bars, and so on when turning the movable plate, and the reflected light exerts a harmful influence on the image as the stray light.
Similarly, in the optical scanner described in the Document 2, since the function of preventing the light reflection on the side surfaces of the beam sections, the fixed section, and so on becomes insufficient, there arises a problem that the stray light exerts a harmful influence on the image.